Typically, devices for measuring electric current may include at least one probe sensitive to a magnetic flux and arranged in an air gap of an annular core. At least one conductor passes through the core. A current to be measured passes through the conductor and generates a magnetic field. A voltage source supplies current to a compensation winding wound on the core that generates a second magnetic field. The probe measures the combined effects of the two magnetic fields and controls the voltage source such that the second magnetic field cancels the first magnetic field. As shown in FIG. 1, this results in a compensating current (IM) that is proportional to the current under measure (IS). The compensating current (IM) can then be measured based on the voltage and a known resistance.
Such methods and systems rely on the measurement accuracy of the probe around zero magnetic field. Many factors, such as ambient air temperature, device drifting and offsets, and sensor resolution can affect the measurement accuracy of the probe. Additional circuitry and/or specific calibrations can be used to compensate for the various factors affecting measurement accuracy. Such additions can be costly.